Ignition System
When making electrical connections to the ignition system, use the same gauge wire (or larger)
as used on the red and black power leads on the ignition module, all the way to the battery pack.
Keep wire lengths to a minimum. Please use the heavy-duty connector plugs supplied with the
ignition or something similar.
Use a high quality switch such as a Futaba or JR heavy-duty switch. Small size R/C receiver
switches are not recommended.
The ignition module must be soft mounted to prevent vibration damage. DO NOT HARD
MOUNT OR USE DOUBLE SIDED TAPE! Zip ties can also be too firm. We recommend Velcro
fabric straps ( The sew on type material). Slots are cut in the motor box, bulkhead, or mounting
plate allowing the Velcro strapping to be threaded through and then wrapped around the
module. Place a piece of high density foam rubber between the ignition and the mounting
surface. If Zip ties are going to be used, wrap the module in foam rubber first.
Isolate the charge circuit from the ignition while charging the batteries. In other words, don’t
“charge” the ignition module while charging the battery. Most receiver switches do this
automatically.
Use 4.8 volt 4 cell, or 6.0 volt 5 cell battery packs only. (We see no significant difference in
engine performance between the two.) While the ignition unit is rated for 4.8 to 6 volt packs, it
will handle the higher voltage they actually produce, including the high “peak” voltage right after
charging. Higher voltage batteries will damage the ignition system and will void the warranty.
We recommend a 1500 mAh or larger pack. With this size pack, the ignition pack should
typically last longer than your receiver pack will. If a standard no load meter shows 5.0 volts or
less, don’t fly. Re-charge. Use a 5.2 to 6.0 volt regulator on packs rated above 6.0 volts.
When connecting the red pick-up sensor to the ignition module, make sure that the
polarity of the wires entering the connectors is correct (Brown to brown, orange to
orange)
Unlike some ignitions, the Desert Aircraft ignition is designed to spark only when the prop is
flipped at a high speed. If the prop is not turned over at “starting” speed, the ignition will not fire.
This helps to prevent the motor from firing accidentally. Unless you are having problems starting
the motor, we don’t recommend “testing” the ignition with the plug removed from the cylinder.
Do not operate the ignition without a spark plug properly installed in the cap! Doing so
will damage the ignition!
When removing the spark plug cap, PULL STRAIGHT out on the cap, not the shielded ignition
wire! Do not use pliers to grip the plug cap! If the cap seems loose, and is not making a solid
metal-to-metal contact with the spark plug base, contact Desert Aircraft for a replacement. To
prevent radio interference, the spark plug caps must have the split retainer ring around their
base – DON’T FLY WITHOUT THEM!
Protect the shielded plug wire from rubbing against fiberglass or sharp edges of wood or
metal! Rubber grommets and plastic “spiral wrap” insulation from automotive or electronic
supply stores work well to protect your braided shielding. Holes in the braided shielding can
emit R/F noise (i.e: RADIO INTERFERENCE!) Damaged plug wires are not replaceable and
may require the ignition to be replaced! Protect them!
Keep ignition components and wiring separated as much as possible from your receiver,
receiver battery, servos, wiring and switches.
Don’t use metal-to-metal linkages to operate the throttle or choke.
Timing is set at the factory and should not need adjustment. Contact Desert Aircraft if you have
any questions regarding timing.
Only use NGK CM-6 spark plugs. Other plugs may not fit the plug caps firmly and cause poor
running or radio interference.
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